The only problem I see with the multiple shadow priests is comparing them with other dps classes, in comparison their rotation is a bit overly mechanical, their aoe is limited, and their cc is limited as well and the curse removal can be a problem. Previously I would have added the very limited range of mindflay as a problem. They obviously have a lot of survivability and on tank and spank boss fights or single kill order trash they are easy mode. Might be a tight spot in wave attack situations.